The effects of external cues on eating and body weight: Another look at obese humans and rats.

Abstract

Schachter's externality theory says that obese individuals are more sensitive to external cues, and Nisbett's extension speculating that obese humans tend to be hungry because they are dieting suggest that external cues should have a greater impact on both obese and dieting animals. The effects of external food cues on food restricted rats and rats fed ad libitum was studied over time. Schachterian predictions about the intake of “obese” (ad lib) or “restrained” (calorically restricted) rats were tested both during and following caloric restriction. A main effect of food cues indicated that both restricted and ad lib rats ate more when food cues were present. During restriction, the restricted rats with food cues present were faster to begin eating (ate more in the first 2 h after food was presented) than either ad lib rats (with or without food cues) or restricted rats without food cues present. Most interestingly, there was a main effect of food cues on body weight such that rats who lived in the presence of food cues weighed more than did those without them. The implications of these findings for Schachter's externality theory will be discussed.